The history of the universe — from the Big Bang to the end of the year — day by day

Amborella Day

The Triassic ends 201 million years ago with another major mass extinction (the fourth, after the end-Ordovician, end-Devonian, and end-Permian). Not quite as bad as the end-Permian, (“only” 75% of species go extinct), maybe the result of volcanoes spewing carbon dioxide as Pangaea splits into Laurasia (North America, most of Eurasia) and Gondwanaland (South America, Africa, Antarctica, India, Australia).

The succeeding Jurassic Period will be when dinosaurs become the dominant vertebrates on land. The mammals around are mostly shrew-sized and nocturnal.

Not as conspicuous is another evolutionary innovation: the ancestors of Amborella, a rare shrub found in the wild only on New Caledonia, split off from the other angiosperms, ancestors of all other flowering plants, 200 million years ago. (This was suspected for a while, and confirmed in 2012 with the sequencing of the Amborella genome.) We can call this the origin of flowers. Amborella has clusters of small white flowers, male and female separate.

People expect to get flowers on Mother’s Day and Valentine’s Day, but not on March 17, 204-193 million years ago on Logarithmic History (Saint Patrick’s Day to the rest of the world). So surprise someone with flowers for Amborella Day!